VPN's
How VPN Tunneling Technology Works
Virtual private
networks may be new, but the tunneling technology they're based on is well established.
Tunneling is a way to
transfer data between two similar networks over an
intermediate network. Also called "encapsulation," tunneling encloses one type
of data packet into the packet of another protocol,
in this case TCP/IP. VPN tunneling adds another dimension to the tunneling
procedure--before encapsulation takes place, the
packets are encrypted so the data is unreadable to outsiders. The encapsulated packets
travel through the Internet until they reach their
destination, then the packets are separated and returned to their original format.
Authentication technology is employed to make sure
the client has authorization to contact the server.
Several firewall providers include virtual private networks as a
security feature. A firewall, which can be software for a host system or a router,
or combination of software and hardware devices,
checks, limits, and logs network access. For additional security, a firewall can encrypt
data
at a site before shipping it out over the Internet.
The receiving site, which must have a matching encryption scheme, can decrypt the data.
Virtual Private Networking
technology provides the medium to use the public Internet backbone as an appropriate
channel for
private data communication. With encryption and
encapsulation technology, a VPN essentially carves out a private passageway
through the Internet. VPNs will allow remote offices,
company road warriors, and even business partners or customers to use the
Internet, rather than pricey private lines, to reach
company networks.
By
replacing expensive private network bandwidth with relatively low-cost bandwidth, your
company can slash operating costs
and simplify communications. You don't need to have
800 lines, run modem pools, or pick up long-distance charges; employees
and business partners simply place local or toll-free
calls to Internet Service Providers (ISPs) to make the connection. Setting
up VPNs also allows you to reduce in-house network
management responsibilities. You'll be able to turn much of
the remote communications burden over to ISP's.
You can also use VPNs to
link remote LANs together or give traveling staffers, work-at-home employees, and business
partners a simple way to reach past company firewalls
and tap into company resources. Virtual private networks are
flexible. They are point-to-multipoint connections,
rather than point-to-point links. They can be set up or closed down at
the network administrator's will, making them ideal
for short-term projects.
Businesses will cut costs with a VPN
Cheaper than leased lines
There's a realization that the public, packet-based
network is far more cost-effective than a leased network because you
can share the fixed cost among many organizations
using the circuit. The public network provides greater scalability and leverage at a lower
cost.
A typical
T1 leased line between a corporation and a local Internet service provider costs $400 to
$500 per month. However,
because T1 charges mount as distance increases, a T1
connection running across the country can cost thousands of dollars each month.
At a glance Virtual Private Networks
Advantages
Much cheaper for connecting WANs than 800 numbers or
dedicated T1 lines
Provides encryption and authentication services for a fairly good measure of privacy
Maintenance of the WAN-to-WAN connection is left to Internet Service providers
Highly flexible; can be set up and taken down very easily
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